Mounting structure for earth moving apparatus



May 10, 1966 MOUNTING Filed Oct. 1, 1965 E. E. DORKINS 3,250,410

STRUCTURE FOR EARTH MOVING APPARATUS 6 Sheets-Sheet l MOUNTING STRUCTURE FOR EARTH MOVING APPARATUS Filed 0013. l, 1965 May 10, 1966 E. E. DORKINS 6 Sheets-Sheet a y 1966 E. E. DORKINS 3,250,410

MOUNTING STRUCTURE FOR EARTH MOVING APPARATUS Filed Oct. 1, 1965 6 Sheets-Sheet 5 y 1966 E. E. DORKINS 3,250,410

MOUNTING STRUCTURE FOR EARTH MOVING APPARATUS Filed Oct. 1, 1965 6 Sheets-Sheet 4 /67 /72 /76 1 I 160 Ma H I /70 H L I ll l 2 FEJU y 1966 E. E. DORKINS 3,250,410

MOUNTING STRUCTURE FOR EARTH MOVING APPARATUS Filed Oct. 1, 1965 6 Sheets-Sheet 5 May 10, 1966 E. E. DORKINS 3,250,410

MOUNTING STRUCTURE FOR EARTH MOVING APPARATUS 6 Sheets-Sheet 6 Filed Oct. 1, 1965 tall United States Patent 3,250,410 MOUNTING STRUCTURE FOR EARTH MOVING APPARATUS Evan E. Dorkins, Holden, Mass, assignor, by direct and mesne assignments, of one-half to Wain-Roy Corporation, Hubbardston, Mass, a corporation of Massachusetts, and one-half to Internatipnal Harvester Company, Chicago, 111., a corporation of New Jersey Filed Oct. 1, 1965, Ser. No. 492,139 29 Claims. (Cl. 214-138) The present application is a continuation-in-part of applicants prior copending application Serial No. 393,156, filed August 31, 1964, for Earth Moving Equipment, now abandoned.

The present invention relates to earth-moving equip ment, and more particularly to an improved mounting structure for attaching an implement, e.g., a backhoe, to a vehicle.

Excavation equipment of the backhoe type, adapted to be attached to the rear of a conventional tractor or otherwise carried on a motor vehicle, is increasingly coming into widespread use. One fault commonly present in the backhoes of the character heretofore known is that they are not well adapted to the digging of a trench parallel to and closely adjacent to an obstruction such as a building. Efforts to solve this problem have been made but the results of all such past efforts have lacked one or another desirable feature.

An object of the invention is to provide an improved implement supporting structure wherein the implement may quickly and conveniently be moved transversely of the vehicle into an operative position close to the side of the vehicle.

Another object is to provide such apparatus wherein the implement supporting structure may be mounted well forward on the vehicle and yet, nevertheless, may be adjusted to move the implement sidewise of the vehicle into positions close to or beyond the vehicle outline.

A further object is to provide such an apparatus wherein the operators station may be so located, in all adjusted positions of the equipment, that the operator can conveniently and effectively observe the operation of the implement.

A further object is to provide such supporting structure particularly adapted to use with a backhoe.

Other objects, features and advantages of the invention will become apparent from the following description of particular illustrative embodiments thereof, in which description reference is made to the accompanying drawings, wherein FIG. 1 is a Side elevation of the backhoe and its supporting structure showing only so much of the vehicle as is required to show the relationship of such structure thereto;

FIG. 2 is a horizontal sectional view on line 22 of FIG. 1;

FIG. 3 is a detail horizontal view to an enlarged scale of parts of the backhoe supporting structure;

FIG. 4 is a vertical mid-sectional view takenpn line 44 of FIG. 3, looking in the direction of the arrows;

FIG. 5 is a vertical transverse sectional view taken on line 55 of FIG. 3;

FIG. 6 is a vertical sectional view taken on line 66 of FIG. 3;

FIG. 7 is a horizontal view similar to FIG. 3 but showing a modification;

FIG. 8 is a vertical sectional view taken on line 8-8 of FIG. 7;

FIG. 9 is a view similar to FIG. 7 but showing the backhoe supporting structure in one of its extreme sidewise adjusted positions;

FIG. 10 is a view similar to FIG. 7, somewhat diagrammatic, showing a further modification;

3,250,410 Patented May 10, 1966 FIG. 11 is an elevation showing a still further modification; and,

FIG. 12 is a plan view of the modification of FIG. ll.

In accordance with the invention I provide an implement supporting structure adapted for permanent or detachable attachment to a vehicle, such as a tractor, and having two coplanar, horizontal, transverse beams mounted thereon in horizontally spaced relation and including a yoke member adapted to carry on its rear end, for sideto-side swinging movement, the swing frame for mounting the implement, such as a backhoe. The yoke member is supported by both beams for horizontal movement transversely of the vehicle and lengthwise of both beams and for pivotal movement such that in its central position the yoke lies along the axis of the tractor for normal operation but in its extreme lateral positions the yoke is displaced angularly with respect to the vehicle axis, in effect being displaced from its central position about a vertical axis located forwardly of the forwardmost beam. Preferably the operators station, including a seat for the operator, is mounted on the yoke member and therefore is displaced laterally of the vehicle when the backhoe is moved to the side, and in the same direction as the backhoe. Preferably means is carried on the yoke for swinging the swing frame and thereby the backhoe. Preferably means is provided for releasably locking or fixing the yoke in its adjusted position on the beams. The particular constructions and arrangements of parts for carrying out the foregoing will be described in more detail hereinafter.

Referring to the drawings, and first to FIGS. 1 to 6, in general organization the apparatus shown comprises a backhoe 2, backhoe supporting structure 4, and a vehicle 6 on which the supporting structure 4 is mounted.

The backhoe comprises a boom 8 supported for vertical swinging movement on a horizontalaxis at 10. A dipper stick 12 is mounted for vertical swinging movement on the boom 8 and carries pivoted on its lower end the backhoe bucket 14. A hydraulically actuated cylinder and piston, indicated generally at 16, is provided for swinging the bucket 14 on the dipper stick 12. Another hydraulically actuated cylinder and piston 18 is provided for swinging the dipper stick 12 with respect to the boom 8 and still another hydraulically actuated cylinder and piston 29 is provided for lifting and lowering the boom 8 about its horizontal axis 10. The backhoe is conventional in construction and need not be described in further detail. The vehicle is provided with a suitable source of pressure fluid for operating the various cylinders and pistons, as is conventional.

The backhoe as an entirety is carried on a swing frame 22, the lower end of the boom 8 being pivoted on the swing frame 22 at 10 and the boom operating cylinder and piston 20 being connected between the boom 8 and a pin 24 located near the top of the swing frame 22. The swing frame 22 is adapted to swing from side to side on the supporting structure about its vertical pivot 26 and to have such swinging movement imparted to it by a hydraulically operated motor 28 or other swing means to be described hereinafter.

The support structure 4 comprises a frame 30 which is stationary and is permanently or detachably mounted on the rear end of the vehicle 6 in any suitable fashion, as is well known in the art, for example by bolting it at 31, as shown, to a fitting 31' fixed to the frame of tractor 6. The frame 30 comprises a first beam 32 extending transversely of the tractor, disposed horizontally, and, in this modification, substantially straight, and a second beam 34 disposed forwardly of the firstbeam 32. The beams are interconnected by frame side members 36 and 38 and a rear frame member 39. The first beam 32 may, if desired, carry vertical channel members 40 and 42 on each end thereof for the mounting of stabilizer arms, as is 3 known in the art. The first beam 32 is built up from two spaced vertical plates 44 and 46 to which are welded respectively channel members 48 and 50, with the channels facing back to back and spaced apart to provide therebetween a straight trackway 52 extending substantially from one end to the other of beam 32. The rear frame member 39 is welded to the plate 46. The beam 34 is provided with a trackway 54 extending lengthwise thereof which is shaped so that its extreme end portions 56, 58 lie closer to the beam 32 than does its central portion 60.

Mounted on the beams 32 and 34, for horizontal sliding movement lengthwise thereof and for pivotal movement about a vertical axis, is a yoke member 62. The yoke member 62 is built up from an upper plate 64, a lower plate 66, and a web 68 interconnecting these plates at their rearward end. The plates 64 and 66 are further interconnected by a vertical plate 70, connected to the two plates 64, 66 and to the web 68. A further horizontal member 72 and a vertical plate 73 are interconnected between the web 68 and the plate 64. Side members 74, 75 (FIG. are joined to plates 64 and 72. Conveniently the yoke member is built up from its component parts by welding them together. The driving motor 28 for the swing frame 22 is mounted on the rear end of the plate 64 and has a shaft extending downwardly through a bearing boss 76, the lower end of the shaft being fixed to the swing frame 22 for operation thereof. At its forward end the plate 64 carries a downwardly projecting boss 78. A vertical pin 80 passes through'the boss 78 and through the trackway 54 in beam 34, being provided with a washer 82 and nut 84 on its lower end to loosely secure the front end of the yoke 62 to beam 34 for lateral movement of the pin 80 along the trackway 54. An operators platform 86 additionally is carried on the yoke and the upper end of the pin 80, an operators seat 88 being also mounted on the yoke, as by mounting it on the plate 86, for movement with the yoke. On a rearward portion of the yoke is mounted a roller 90 which runs in the trackway 52 of the beam 32. Conveniently the roller 90 may be carried on a pin 92 passing through plate 64 and plate 72 and carrying washers 94, 94' at its upper and lower ends, held in place thereon by nuts 96, 96'.

To aid in maintaining the yoke member 62 in proper position to follow both track 52 and track 54, a third track 98 may be provided in the frame member 39 for the reception of a pin 100 fixed in the plate 72, the track 98 being shaped like the track 54 but with less angularity between its two portions lying one on each side of the center line.

Preferably means for clamping the yoke 62 in its adjusted position is provided. This may take the form of a vertical shaft 102 journaled in plates 64 and 72 and carrying an eccentric 104 at its lower end and an operating handle 106 on its upper end. Rotation of shaft 102 by movement of handle 106 rotates the eccentric 104 to cause it to jamb against the rear face of vertical plate 44, thus releasably locking the yoke 62 in place.

In operation the yoke member 62 may be moved out of its central position shown in FIG. 3 into any desired lateral position, for example, by releasing the eccentric 104, lowering the backhoe into engagement with the earth and operating the appropriate controls to cause swinging movement of the frame 22 by means of the motor 28. In such movement the roller 90 moves along the track 52 and as it does so the pin 80 also moves along the track 54 and the pin 100 along track 98. Inasmuch as the track 54 converges toward the track 52 but the spacing between roller 90 and pin 80 remains constant, the roller 90 and the rear end of the yoke 62 must move further than the pin 80 and the forward end. Conveniently the inclination of the two portions of the track 54 may be made such that when the roller 90 reaches the end of the track 52 the pin 80 also will reach the end of the track 54 on the corresponding side of the apparatus. Thus, in moving laterally, the yoke 62 is, in effect, displaced from its cenremain well forward, between the tires 108.

tral position about a vertical axis which is located forwardly' of the beam 34. This arrangement enables the rearward end of the yoke to be displaced so far laterally as to lie behind or even outwardly of the vehicle tires 108, while permitting the forward end of the yoke to At the same time the operator is moved to the side to which the backhoe is moved so that he will be able to see into the trench comfortably and yet remain safely positioned between the limits established by the tires 108.

A modification of theconstruction described above is illustrated in FIGS. 7, 8 and 9. In this modification, the stationary frame member is built up from a plate 110 welded at its rearward edge to a vertical plate 112, forming part of a first beam 114, and carrying at its forward edge a second beam 116 which is straight and shorter than beam 114. The first beam 114 further comprises two channels 118, 128 and a second vertical plate 122 all welded together, as shown, the channel being spaced to provide a trackway 123 on the first beam 114. The beams 114 and 116 are further connected together by vertical side frame members 124, 126, one at each end of beam 116, and having bolt receiving holes 128, 128 for bolting the stationary frame member to the tractor.

The yoke member 129 comprises a horizontal plate 130 carrying at its forward end a bracket 132 having at inturned lip 134 for engagement beneath the beam 116 and carrying a forwardly extending plate136 forming a platform for the operators station, including a seat for the operator. At its rear edge the plate 130 carries a lower pivot 138 and an upper pivot 140 for mounting the swing frame 22 on the yoke member 129. The swing frame 22 is adapted to be swung from side to side about its pivots 138, 140 on the yoke 129 by means of a pair of swing cylinders 142, 144 pivoted on the yoke at 146 and having their piston rods connected respectively to links 148, 150 in turn connected to a rotary post member 152 fixed to the swing frame 22 coaxial with its pivots. A roller 154 carried on a rearward portion of the yoke 129 runs in the trackway 123 provided by the channels 118, 120.

Fixed to the under surface of the plate 130 is a guide plate 156 having its forward edge in position to bear against the rearward face of the upper portion of the vertical plate 112 when the yoke is in its central position on the beams 114 and 116. When the yoke is moved sidewise on the beams, the plate 156 maintains the yoke approximately parallel to the longitudinal axis of the vehicle until the yoke approaches or reaches the end of its travel on the beam 116. Thereupon the bracket 132 engages the side frame member 126 to prevent further movement of the forward end of the yoke end-wise of the beam 116. Thereafter the yoke pivots with respect to the beams into the position shown in FIG. 9, the top edge of the vertical plate 112 being cut away at 112' between the end of the beam 116 and the point 158, FIG. 7, to permit the plate 156 to clear the vertical plate 112 in such pivoting movement.

The modification of FIGS. 7, 8 and 9 may be provided with means for locking the yoke in its adjusted position, and may have the operators seat carried on the yoke 129, as in the modification of FIGS. 1-6. In FIG. 7 the yoke is shown in its central position and in FIG. 9 is shownin its extreme lateral position at one side of the implement. It will be observed that in moving from its central position to its extreme position the yoke has been displaced from its central position about a vertical axis located forwardly of the beam 114.

In FIG. 10 is illustrated schematically a further modification wherein the yoke 160 is supported on a first, or rearward, beam 162 and a second, or forward, beam 164. The first beam 162 carries a trackway 166 and a second beam 164 is provided with a trackway 168. Both trackways are curved about a common vertical axis located at 170, forwardly of the second beam 164. The yoke 160 carries means, such as a roller 172 of the type heretofore described, on a rearward portion of the yoke for engaging the trackway 166 and constraining said rearward portion of the yoke to follow said trackway. The yoke also is provided on a forward portion thereof with means such as a pin 174 of the type heretofore described engaging the trackway 168 for constraining the forward portion of the yoke to follow thetrackway 168. The yoke carries on its rearward end a motor 176 for swinging the swing frame as in the other modifications, which swing frame in turn supports the boom of the backhoe. Means may be provided for releasably locking the yoke 160 in any desired position and for mounting the operators station on the yoke. p

The roller 172 may be replaced by two rollers spaced from each other in the lengthwise direction of beam 162 and running in the trackway 166 or running on the forward face of beam 162, which then servesas a trackway. The rearward face of beam 164 similarly may serve asthe trackway for roller or pin 174 when roller 172 is so replaced by two rollers.

In FIGS. 11 and 12 there is illustrated a still further embodiment of the invention, wherein a yoke member 180 is supported on a first outer arcuate beam 181 and second inner arcuate beam 182 which form part of a framework releasa-bly secured to the rear of the tractor and which are curved, as shown, about a common axis lying forwardly of the inner beam 182. The framework additionally includes downwardly directed side members 183 and 184 which are connected at their uppermost ends to the ends of the arcuate beam 181 and at their lowermost ends to a lower horizontal cross beam 185. The upper ends of the side members 183 and 184 are connected by beams 186 and 187 to the ends of the inner arcuate beam 182 and side plates 188 and 189 are provided which are connected at their uppermost ends to the ends of the arcuate beam 182 and at their lowermost ends to the cross beam 185 where they are strengthened by box sections 190 and 191. The framework is supported on the tractor by rearwardly extending brackets 195 and 197 to which the framework is connected by bolts which pass through holes in the rear ends of the brackets and through bosses 198 and 199 provided on plates 200 and 201 formed on the ends of the box sections 190 and 191 and by links 192 and 193 to which the framework is also connected by bolts which pass through holes in the links and through bosses 194 and 195 carried by lugs projecting from the beam 182 at the ends thereof.

Each of the said members 183 and 184 carries a hydraulic cylinder 202 which is mounted at its upper end on a pivot 203 carried by the side member 183 and operates a piston rod 204 the lower end of which is pivotally connected to a stabilizing leg 205 pivoted at one end on a pivot pin 206 located at the end of the transverse beam 185 and carrying at its other end a foot 207, the arrangement being such that the leg 205 can be lowered by the operation of the hydraulic cylinder 202 to bring the foot 207 into engagement with the ground to serve as a stabilizer.

All the component parts of the framework are connected together by welding. The outer arcuate beam .181 is formed by welding together two channel sections 208 and 209 as illustrated in broken line in FIG. 11 and the inner arcuate beam 182 is formed in the same manner.

The yoke member 180 comprises an upper horizontal platform 210 having on each side thereof a downwardly extending plate 211 which joins an upper horizontal plate 212 of a box section having on each side a downwardly extending plate 213, and an inclined base plate 214, the box section extending rearwardly beneath the arcuate beam 181 where it is provided with a rearwardly extending bracket 215 which is adapted to support the pivot for a swing frame 217 which is pivotally supported at its upper end in a bearing 216 in the rear of the upper platform 2 10. The box section passing beneath the arcuate beam 181 is provided with a horizontal bearing plate 218 which is adapted to bear upwardly against the beam 181 under predetermined loading conditions of the yoke member 180. The side plates 21 1 are connected in the region tabove the arcuate beam 181 by an upper horizontal hearing plate 219 which under opposite loading conditions of the yoke member bears down on theupper surface of the beam 181. Each of the side plates 211 is furthermore provided with a laterally projecting horizontal plate 220 which carries a boss which serves as an upper bearing for a roller 222 the lower end of which is received in a bearing 223 formed in the bearing plate 218, the arrangement being such that the roller 222 on each side of the yoke member bears against the inner face of the beam 181 and serves to control the movement ofithe yoke member 180 in a manner hereinafter described. The bearing plate 218 carries two further rollers 224 and 225 which are arranged to cooperate with the outer face of the beam 181 and also serve to control the movement of the yoke member 180. The inner or forward end of the box section, which comprises the upper plate 212, the two side plates 213 and the inclined base plate 214, terminates with an end plate 238 which carries freely rotatable upper and lower rollers 226 and 227, the upper roller 226 being adapted on appropriate loading of the yoke member to bear down on the upper surface of the arcuate beam 182 and the lower roller 227 being adapted on appropriate opposite loading of the yoke member to bear upwardly against the lower surface of the beam 182.

It will be seen that the yoke member 180 is constrained by the two rollers 222 and the rollers 224 and 225 to move along the length of the beams 181 and 182, turning about the common center of the latter two beams. A fixed chain 228 is provided along the upper outer edge of the beam 181 and a locking number 229 pivotally mounted on the yoke member 180, which can be operated by means of a lever 230, is adapted to be brought into engagement with the chain when the yoke member has taken up the required lateral position so as to lock the yoke member in the required attitude.

The swing frame 217 is arranged to be turned about its vertical axis by an arrangement of hydraulic cylinders- 231 and 232 which operate on piston rods 233 and 234 connected by links 235 and 238 to a swing plate 237 fixed to the swing frame 217, the arrangement being such that an advance of one of the piston rods and a retraction of the other results in a turning movement of the swing frame 217.

In operation when it is desired to move the yoke memher 180 from, say, its center position, the locking member 229 is released and the backhoe is brought into engagement with the ground. Upon an appropriate operation of the hydraulic cylinders 231 and 232 the swing frame 217 is turned and the yoke member caused to move in one sense or the other along arcuate beams 181 and 182v The locking member 229 is then brought into engagement with the chain 228 to hold the yoke member 180 in the new position.

I- claim:

1. An earth-moving apparatus comprising a support member adapted for attach-ment to a vehicle, a first horizontal transverse beam mounted on said support member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced fro-m said first beam forwardly thereof, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement about a vertical axis, said yoke member being fixed against substantial vertical movement with respect to said beams, a swing frame pivoted on the rearward end of said yoke member for movement about a vertical axis,' and an earth-moving implement supported on said swing frame.

2. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support 7 member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement such that in its extreme lateral positions the yoke is displaced from its central position about a vertical axis located forwardly of said second beam, said yoke member being fixed against substantial vertical movement with respect to said beams, an operators seat mounted on said yoke member, a swing frame pivoted on the rearward end of said yoke member for movement about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth-moving implement supported on said boom.

3. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement such that in its extreme lateral positions the yoke is displaced from its central position about a vertical axis located forwardly of said second beam, said yoke member being fixed against substantial vertical movement with respect to said beams, a swing frame pivoted on the rearward end of said yoke member for movement about a vertical axis, means on said yoke member for swinging said swing frame with respect to said yoke member about said last-mentioned vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth moving implement supported on said boom.

4. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement such that in its extreme lateral positions the yoke is displaced from its central position about a vertical axis located forwardly of said second beam, said yoke member being fixed against substantial vertical movement with respect to said beams, means for releasably securing said yoke member against horizontal movement with respect to said beams, a swing frame pivoted on the rearward end of said yoke member for movement about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth moving implement supported on said boom.

5. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member and having a trackway extending longitudinally thereof, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement about a vertical axis located forwardly of said second beam, said yoke member being fixed against substantial vertical movement with respect to said beams, a roller on said yoke member constrained to run on said trackway, a swingframe pivoted on the rearward end of said yoke member for movement about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth moving implement supported on said boom.

6.- An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member and having a first, substantially straight, trackway extending longitudinally thereof, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, said second beam having a second trackway extending longitudinally thereof and having its end portions disposed closer to said straight trackway than areits middle portions, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and .piv-, otal movement about a vertical axis located forwardly of said second beam, said yoke member being fixed against substantial vertical movement with respect to said beams, means on a rearward portion of said yoke member engaging said first trackway for constraining said portion to follow said first trackway, and means on a forward portion of said yoke member engaging said second trackway for constraining said forward portion to follow said second trackway, a swing frame pivoted on the rearward end of said yoke member for movement about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth moving im-. plement supported on said boom.

7. The apparatus of claim 6 wherein an ope-rators seat is mounted on said yoke member. 7

8. The apparatus of claim 6 comprising means on said yoke member for swinging said swing frame with respect to said yoke member.

9. The apparatus of claim 6 comprising means for releasably securing said yoke member against horizontal movement with respect to said beams.

10. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member and having a trackway extending longitudinally thereof, a second horizontal transverse beam mounted on said support member coplanar with and shorter than said first beam and horizontally spaced from said first beam forwardly thereof, a yoke member fixed against substantial vertical movement with respect to both said beams and connected to and supported by both said beams for horizontal movement lengthwise of both said beams, means on 'a rearward portion of said yoke member engaging said trackway for constraining said portion to follow said trackway, means for preventing substantial transverse movement of the forward end of said yoke member beyond the ends of said second beam, said yoke being pivotable about a vertical axis when in positions adjacent the ends of said second beam, a swing frame pivoted on the rearward end of said yoke member for movement about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth moving implement supported on said boom.

11. The apparatus of claim 10 wherein 'an operators seat is mounted on said yoke member.

12. The apparatus of claim 10 further comprising means on said yoke member for swinging said swing frame with respect to said yoke member.

13. The apparatus of claim 10 further comprising means for releasably securing said yoke member against horizontal movement with respect to said beams.

14. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, each said beam having a horizontal trackway thereon, said trackways being curved about a common vertical axis located forwardly of said second beam, a yoke-member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement about said vertical axis, said yoke memher being fixed against substantial vertical movement with respect to said beams, means on a rearward portion of said yoke member engaging the trackway on said first beam for constraining said portion to follow the trackway on said first beam, means on a forward portion of said yoke member engaging the trackway on said second beam for constraining said forward portion to follow the trackway on said second beam, a swing frame pivoted on the rearward end of said yoke member about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth-moving implement supported on said boom.

15. The apparatus of claim 14 wherein an operators seat is mounted on said yoke member.

16. The apparatus of claim 14 further comprising means on said yoke member for swinging said swing frame with respect to said yoke member.

17. The apparatus of claim 14 further comprising means for releasably securing said yoke member against horizontal movement with respect to said beams.

18. An earth moving apparatus comprising a support member for attachment to a vehicle, a first horizontal transverse beam mounted on said support member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, said beams being curved about a common vertical axis located forwardly of said second beam, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement about said vertical axis, said yoke member being fixed against substantial vertical movement with respect to said beams, means on a rearward portion of said yoke member engaging said first beam for constraining said yoke member to turn about said vertical axis, a swing frame pivoted on the rearward end of said yoke member about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earthmoving implement supported on said boom.

19. The apparatus of claim 18 wherein a chain of links is fixed to said first beam and a locking device is provided on said yoke and is movable between a locking position in which a projection thereon is in engagement with said chain and a release position in which it is clear of the chain.

20. The apparatus of claim 18 wherein an operators seat is mounted on said yoke member.

21. The apparatus of claim 18 further comprising means on said yoke member for swinging said swing frame with respect to said yoke member.

22. The apparatus of claim 18 further comprising means for releasably securing said yoke member against horizontal movement with respect to said beams.

23. The apparatus of claim 18 wherein said constraining means comprises a pair of spaced rollers carried by said yoke member and arranged to bear against the forward face of said first beam and another pair of rollers carried by said yoke member and arranged to bear against the rearward face of said first beam.

24. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, said beams being curved about a common vertical axis located forwardly of said second beam, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement about said vertical axis, said yoke member being fixed against substantial vertical movement with respect to said first beam, a pair of rollers on a forward portion of said yoke member engaging horizontal surfaces on said second beam for preventing substantial vertical movement of the forward end of said-yoke member, a swing frame pivoted on the rearward end of said yoke member about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth-moving implement on said boom.

25. An earth-moving apparatus comprising a support member adapted for attachment to a vehicle, a first horizontal transverse beam mounted on said support member, a second horizontal transverse beam mounted on said support member coplanar with said first beam and horizontally spaced from said first beam forwardly thereof, said beams being curved about a common vertical axis located forwardly of said second beam, a yoke member connected to and supported by both said beams for horizontal movement lengthwise of both said beams and pivotal movement about said vertical axis, said yoke member being fixed against substantial vertical movement with respect to said first beam, means on a rearward portion of said yoke member engaging said first beam for constraining said yoke member to turn about said vertical axis, a pair of rollers on a forward portion of said yoke member engaging horizontal surfaces on said second beam for preventing substantial vertical movement of the forward end of said yoke member, a swing frame pivoted on the rearward end of said yoke member about a vertical axis, a boom supported on said swing frame for movement about a horizontal axis, and an earth-moving implement supported on said boom.

26. The apparatus of claim 25 wherein an operators seat is mounted on said yoke member.

27. The apparatus of claim 26 further comprising means on said yoke member for swinging said swing frame with respect to said yoke member.

28. The apparatus of claim 27 further comprising means for releasably securing said yoke member against horizontal movement with respect to said beams.

29. The apparatus of claim 28 wherein said constrain ing means comprises a pair of spaced rollers carried by said yoke member and arranged to bear against the forward face of said first beam and another pair of rollers carried by said yoke member and arranged to bear against the rearward face of said first beam.

References Cited by the Examiner UNITED STATES PATENTS 3,117,685 1/1964 Davis 214-138 FOREIGN PATENTS 1,310,448 10/1962 France.

HUGO O. SCHULZ, Primary Examiner. 

1. AN EARTH-MOVING APPARATUS COMPRISING A SUPPORT MEMBER ADAPTED FOR ATTACHMENT TO A VEHICLE, A FIRST HORIZONTAL TRANSVERSE BEAM MOUNTED ON SAID SUPPORT MEMBER, A SECOND HORIZONTAL TRANSVERSE BEAM MOUNTED ON SAID SUPPORT MEMBER COPLANAR WITH SAID FIRST BEAM AND HORIZONTALLY SPACED FROM SAID FIRST BEAM FORWARDLY THEREOF, A YOKE MEMBER CONNECTED TO AND SUPPORTED BY BOTH SAID BEAMS FOR HORIZONTAL MOVEMENT LENGTHWISE OF BOTH SAID BEAMS AND PIVOTAL MOVEMENT ABOUT A VERTICAL AXIS, SAID YOKE MEMBER BEING FIXED AGAINST SUBSTANTIAL VERTICAL MOVEMENT WITH RESPECT TO SAID BEAMS, A SWING FRAME PIVOTED ON THE REARWARD END OF SAID YOKE MEMBER FOR MOVEMENT ABOUT A VERTICAL AXIS, AND AN EARTH-MOVING IMPLEMENT SUPPORTED ON SAID SWING FRAME. 